Policy makers and researchers who need detailed information on the variety of treatment programs drug offenders received and on the effectiveness of those programs must take into account programs run by prisons, probation, and parole. First, most offenders are serious drug users, so in general most of the "clients" of correctional programs are drug users. Second, practitioners and researchers in the field of drug abuse need to know not only about treatment effects on substance abuse, but also on other life consequences, such as rates of criminality, unemployment, and psychological symptomatology. In The effectiveness of Correctional Treatment: A survey of Treatment Evaluation Studies (1975), Lipton, Martinson, and Wilks systematically annotated evaluation studies of probation, imprisonment, parole, psychotherapy, group methods, and other correctional-based rehabilitation programs (written between 1945 and 1967) and assessed the relative effects of these treatments on recidivism, institutional adjustment, educational achievement, drug and alcohol readdiction, and other outcomes. Since that work, there have been great improvements in the scientific quality of reviews, including new statistical methods termed meta-analysis. Consequently, CDATE was funded in 1994 to conduct a state-of-the-art, world-wide meta-analytic review which would be more comprehensive than any one of the several meta- analyses conducted in the intervening years could have been. At the time of the initial proposal, CDATE estimated that about 500 new studies on correctional treatment would have been generated in the 1968-1995 period. For the past two-and-half years CDATE has been searching worldwide for unpublished as well as published research studies, annotating them, coding them (using an extremely thorough codebook) and conducting preliminary meta-analyses of the effects of various treatments on drug use, crime, and other outcomes. In fact, we find that there are about 1,000 more research studies to code than we expected, i.e., a total of about 1,500 relevant research studies. Our annotating and coding work is about three times greater that what we expected. On the one hand, it is a wonderful discovery to have three times as many research studies to draw upon, covering as they do many different - treatment programs and many diverse client groups. On the other hand, annotating and coding 1,500 research reports rather than 500 means that we need an additional year to finish the systematic annotations and analyses. Thus, we propose an additional year to take advantage of the abundance of research knowledge we have found.